Method for producing braided spiral reinforced hose

ABSTRACT

A flexible hose having a novel braided reinforcement layer wherein one braid member is a relatively stiff, uncrimped monofilament and the second braid member is a flexible textile material which is crimped around the stiff monofilament at each contact point in the braided spiral layer. The braided spiral imparts improved crush and kink resistance to the hose structure. The method of manufacture employs no mandrel and produces a balanced tension braided hose which may be preferably cured by open steam techniques.

This is a division of application Ser. No. 731,759 on May 8, 1985, nowU.S. Pat. No. 4,553,568, which is a continuation of application Ser. No.562,665 filed Dec. 19, 1983, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a reinforced hose structure and moreparticularly to a hose having improved crushed resistance through theuse of a braided spiral sleeve in which a first braid member is composedof a relatively stiff uncrimped monofilament which maintains itsuncrimped character during the braiding operation and a second braidmember which is a relatively flexible textile material which crimps ordeforms around the first braid member.

BACKGROUND ART

In applications such as hose used for the dispensing of gasoline, it isdesirable for the hose to be flexible yet be capable of regaining itsshape after being crushed in service. Hose structures are known in whicha liner or tube are covered by two textile braids with a monofilamenthelically wound between the braids. The process for building hoses ofthis construction require a mandrel be used to support the tube duringbraiding and especially during application of the monofilament helixsince the monofilament helix exerts a twisting force on the tube.Expensive methods such as lead press curing or fabric wrap curing arerequired due to the residual twisting force which remains in the uncuredhose during the vulcanizing process.

In accordance with the present invention, a lighter weight reinforcedhose can be produced which has excellent resistance to kinking. Greatercrush resistance is also imparted which means that the hose will regainits shape after it has been crushed. The hose also has an advantage inthat it has no residual twisting stress and thus remains stable whenplaced under internal working pressure exhibiting no twisting inservice. These advantages are accomplished by utilizing a flexible hosecomprising an elastomeric tube, a braided spiral sleeve surrounding saidelastomeric tube having a first braid member and a second braid memberunder equal tension, said first braid member being composed of at leastone strand of relatively stiff, uncrimped monofilament helically woundabout said elastomeric tube, said second braid member being composed ofa plurality of relatively flexible, crimped textile filaments helicallywound oppositely to said first braid member and interwoven with saidfirst braid member such that said second braid member is crimped at eachpoint of contact with said first braid.

The method used for manufacturing the hose of this construction has theadvantage of being a non-mandrel hose building process and is adaptableto fully continuous length production. An additional advantage of themethod of manufacturing of this hose is that economical curing methodssuch as open steam, continuous vulcanization utilizing molten salt orhot heat transfer medium, or various fluid bed continuous curingmethods. These advantages are accomplished by a non-mandrel method ofmanufacturing a flexible hose having braided spiral reinforcementcomprising (a) extruding an unsupported elastomeric tube, (b) applying abraided spiral sleeve around said elastomeric tube, said braided spiralsleeve being composed of a first braid member wound in a smooth helicalpath about said tube and a second braid member being braided with saidfirst braid member wherein said second braid member deforms around saidfirst member at each point of contact between first and second braidmembers, and wherein the tension of first and second braid members aresubstantially equal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a section of a hose showing the preferredembodiment of this invention with a part in section and other partsbroken away for clarity.

FIG. 2 is a diagonal cross-sectional view of the braided spiral sleeveonly as shown in FIG. 1 taken on line 2--2.

FIG. 3 is a diagonal cross-sectional view of the braided spiral sleeveonly as shown in FIG. 1 taken on line 3--3.

FIG. 3a is an enlarged view of a portion of FIG. 3.

FIG. 4 is a simplified schematic representation of the method ofmanufacture of the hose of this invention.

FIG. 5 is a pictorial representation of the hose of this invention usedin a fluid transfer system.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 the hose 10 comprises an elastomeric tube 1 of amaterial suitable for conveying or containing the fluid to betransported. Any suitable rubber or thermoplastic elastomer known to beuseful in hose applications may be used. These may include rubberpolymers, such as polychloroprene, acrylonitrile-butadiene,styrene-butadiene, polyisoprene, ethylene-propylene-diene and naturalrubber polymers. These polymers may be compounded with other knownmaterials to achieve particular properties required for specificapplications. The elastomeric tube 1 is surrounded by a braided spiralsleeve 2 consisting of a first braid member 3 which is composed of oneor more relatively stiff monofilaments which are wound in a smoothhelical path around the elastomeric tube. A single monofilament is shownfor simplicity of illustration although it is to be understood that aplurality of monofilaments may be used to constitute the first braidmember 3. The monofilament may be composed of any synthetic polymersuitable for fabrication into a monofilament having sufficientresistance to kinking to be useful. Polyesters, copolyesters,non-aromatic polyamides such as nylon, aromatic polyamides or fiberglassare the preferred materials for the monofilament of this invention.Polyester is most preferred due to the ease of attaining a strong curedbond with the surrounding elastomeric layers of the hose. Themonofilament diameter is widely variable depending upon the requirementsof the end-use application. Preferably the diameter may range from 0.1to about 10 millimeters, with most preferred being between 0.3 and 2millimeters. The second braid member 4 is wound in a helical patternfrom an opposite direction. The second braid member 4 is interwoven withthe first braid member 3. The second braid member 4 must be veryflexible relative to the first braid member 3. Said second braid membermay be preferably composed of conventionally used textile materials suchas nylon, rayon, polyester, or fiberglass etc., filaments and yarnswhich are loosely twisted into a suitable textile material for braiding.The first braid member 3 follows a smooth helical course and exhibits nocrimping during the braiding operation. The second braid member 4 isinterwoven in a helical pattern from an opposite direction and exhibitscrimping or kinking at each point where it is interwoven with the firstbraid member 3. Both braid members must be under substantially equaltension during the braiding step. After braiding, the relatively stifffirst braid member remains uncrimped and thus lies substantially in animaginary cylindrical surface surrounding said elastomeric tube at theappropriately spaced radial distance from the outer surface of saidelastomeric tube 1. The embodiment shown in FIG. 1 includes aconventional braided textile reinforcement sleeve 5 which may beoptionally utilized if the particular hose application requiresadditional burst strength in the finished hose. A rubber insulationlayer 6 may be applied between braided sleeves if more than one suchsleeve is utilized.

An elastomeric cover 7 is shown surrounding the outer most braided layerand may be composed of any suitable rubber or thermoplastic elastomerknown to be useful in hose constructions.

The equality of tension under which the first braid member and secondbraid member are applied to the underlying structure is critical to theoperation of this invention. The equal tension on each of the componentmembers of the braided spiral is important in two aspects of thisinvention. The first is that the balanced tension on the braidedcomponents allows for a non-mandrel technique to be utilized in hosebuilding since the balanced tension assures that no twisting force isput on the underlying elastomeric tube during its progress through theone or more braiding decks. The second important aspect of this equalbraid member tension is in the finished hose where the equal tensionassures that a stable non-twisting finished hose is produced uponcompletion of the curing step. The angle at which the first and secondbraid members are applied in the braided spiral sleeve is dependent uponthe degree of crush resistance required and the amount of internal burstresistance required in the application. It has been found that the braidangles may vary between 45° and 65° when braid angle is measured as theincluded angle between the braid element and the longitudinal axis ofthe hose. The preferred range is of braid angle is 50°-60°. Optimalcrush resistance is achieved using a braid angle between 53° and 60°.

FIG. 2 is a cross-sectional view of the braided spiral sleeve takenalong line 2--2 which shows more clearly the configuration of the firstand second braid members 3 and 4 respectively after the braiding stephas been completed. The relatively stiff first braid member 3 is shownin cross section as a smooth uncrimped circle which shows more clearlythe smooth helical path of the first braid member. In cross-section thefirst braid member 3 is shown to clearly lie in a smooth cylindricalsurface having a diameter equal to the diameter of the braided spiralsleeve. An alternative description might be that first braid member 3lies within an annular ring of indeterminate length having a widthsubstantially equal to the diameter of said first braid member 3. Secondbraid member 4 is shown in cross-section to be deformed around the firstbraid member 4 at each contact point. Thus unlike the conventionalbraiding methods in which each braid member is deformed around theother, in the method of this invention the first braid member isuncrimped while only the second braid member is deformed or crimpedaround the first braid member.

FIG. 3 is a cross-section of the braided spiral layer in isolation,taken along line 3--3 on FIG. 1. This figure shows the course of thesecond braid member 4 around the circumference of the braided spiralsleeve 2. It can be clearly seen that the second braid member 4 deformsaround the first member during the braiding operation since it iscomposed of a more flexible material than the first braid member. FIG.3a shows an enlarged section of FIG. 3 depicting more clearly theplurality of filaments which constitute the second braid member 4.

FIG. 4 is a simplified schematic representation of the method ofmanufacturing. Solid and flexible mandrel methods may be employed in themanufacture of this hose. Due to the cost and speed advantages inherentin non-mandrel techniques the preferred manufacturing method of thisinvention is an non-mandrel method for producing a braided spiral hose.An unsupported elastomeric tube member 51 is produced using conventionaltube making equipment such as an extruder 52. Tube member 51 mayoptionally have positive pressure applied inside to assist inmaintaining its circular cross-section. FIG. 4 shows the elastomerictube 51 being fed directly to a braider 53 for application of thebraided spiral sleeve. It should be noted that the process formanufacturing the elastomeric tube may be such that it is desirable forthe elastomeric tube to be produced in a separate step and later fedinto the braider 53. Conventional braider equipment may be utilizedprovided that equal tensioning of the individual braid members can bemaintained. The braider may apply one or more braided sleeves to theelastomeric tube in a single pass. The carriers of the braider whichwind a braid member in a first direction must carry the first braidmember, a relatively stiff monofilament. The carriers which apply thesecond braid member from the opposite direction should carry the secondbraid member material. The second braid member is substantially moreflexible than the first braid member and will deform around the stifffirst braid member during the braiding operation.

If a conventional braid reinforcement sleeve is being applied inaddition to one or more braided spiral sleeves, both sets of carriers ofthe braider are loaded with conventional textile reinforcementmaterials. Once the desired number of braided spiral sleeves andconventional braided sleeves have been applied an elastomeric covermaterial may optionally be applied over the braided sleeves by coverapplicator 54. Any conventional process for application of cover layersto a hose may be utilized with the most common method being the use of across-head extruder. The uncured composite hose 55 exits from the coverapplicator 54 and proceeds to the curing process 56. The curing processmay be any conventionally known method of curing or vulcanizing hose.The preferred methods are those in which the uncured composite hose issubJected to the high temperature curing environment immediately with nointervening steps. These methods include open steam curing, fluidizedbed curing, continuous vulcanization using heat transfer media such asmolten salts or hot oil. These direct curing methods are preferred dueto the simplicity, efficiency and resulting low cost. Other moreexpensive curing methods employing additional preparation steps may beutilized to produce the hose of this invention. These include lead presscuring in which a coating of molten lead is applied to the uncured hosecomposite; solidified; and then put in open steam curing or autoclaveequipment for vulcanization. Another curing method in which anadditional step is required is the fabric-wrap method in which fabric isspiraled over the uncured hose composite for the purpose of applyingexternal pressure to the composite prior to the introduction of theuncured hose composite to the high temperature curing conditions. Themost preferred method of manufacturing this hose is by low cost,non-mandrel manufacturing techniques which are not generally compatiblewith the more expensive curing methods such as lead press or fabric wraptechniques.

FIG. 5 illustrates an exemplary embodiment of a fluid transfer system 40which is adapted for transport of flammable liquids such as gasoline orfuel oil. The braided spiral hose 41 of this invention is used incombination with a first coupling 42 which is securely fastened to afirst end of the hose 41 to form a fluid-tight seal. The braided spiralhose 41 is similar in all respects to the hose 10 of FIG. 1. A secondcoupling 43 is securely fastened to a second end of the hose 41 to forma fluid-tight seal. Couplings 42 and 43 are well known and conventionalin all respects and may be selected for the particular application byone skilled in this art. First coupling 42 is attached to a dispensingnozzle 45. The attachment may be rotatable or fixed. Second coupling 43is attached to a pumping apparatus 44, shown as a conventional gasolinepump. The pumping apparatus delivers fluid to the fluid transfer systemfrom a fluid storage means, not shown. The dispensing nozzle 45transfers fluid to a receiving tank 45 such as an automobile tank.

A preferred embodiment of this invention was manufactured for use in afluid transfer system as illustrated in FIG. 4 using an elastomeric tubecomposed of rubber (NBR) blended with polyvinyl chloride (PVC) for usewith gasoline or diesel fuels. The unsupported tube was extrudedcontinuously with no supporting mandrel and fed to a multideck braider.A conventional rayon textile braid was applied in a sleeve directly overthe elastomeric tube. An insulating layer of NBR rubber was then appliedafter the first rayon textile braid. The braided spiral sleeve wasapplied over the insulating layer of rubber. The braided spiral layerwas composed of a first braid member of 0.7 millimeter polyestermonofilament and a second braid member of rayon textile yarn braided inthe opposite direction. The braid angle utilized was 60° in order tooptimize kink resistance and crush resistance and limit expansion of thehose under internal pressure. The first and second braid members wereapplied under equal tension of 2.5 pounds. An NBR/PVC cover was thenapplied by cross-head extrusion over the braided spiral layer. A wireribbon extending the full length of the hose was laid longitudinallyunder the first textile braid for the purpose of conducting staticelectricity. This conductive or bonding wire is required in the gasolinedispensing hose specifications to dissipate static charges and conductany charges to ground. The uncured hose composite was then cured in opensteam.

While a limited number of exemplary embodiments of the invention havebeen shown and described in detail, it will be apparent to those skilledin the art that various changes and modifications may be made thereinwithout departing from the scope of the invention as covered.

We claim:
 1. A non-mandrel method of manufacturing a flexible,kink-resistant hose capable of regaining an original shape aftercrushing having a braided spiral reinforcement comprising:(a) extrudingan unsupported, uncured elastomeric tube; (b) applying a shape-restoringlayer of a braided spiral sleeve around said uncured elastomeric tube,said braided spiral sleeve being composed of a first braid member of arelatively stiff, uncrimped monofilament selected from the groupconsisting of polyesters, copolyesters, aromatic polyamides,non-aromatic polyamides and fiberglass wound in a smooth helical pathabout said tube and a second braid member being braided with said firstbraid member wherein said second braid member deforms around said firstmember at each point of contact between said first and second braidmembers, said second braid member being composed of a plurality ofrelatively flexible, crimped textile filaments and wherein the tensionof the first and second braid members are substantially equal.
 2. Amethod as set forth in claim 1 further comprising the steps of applyingan elastomeric cover surrounding said braided spiral sleeve to form anuncured hose composite and curing said uncured hose composite.
 3. Amethod as set forth in claim 1 further comprising the steps laying astatic conducting wire adjacent to said elastomeric tube; then applyinga textile braided sleeve prior to application of said braided spiralsleeve.
 4. A non-mandrel method of manufacturing a flexible,kink-resistant hose capable of regaining an original shape aftercrushing having a braided spiral reinforcement, said method comprisingthe steps of:(a) extruding an unsupported, uncured elastomeric tube; (b)braiding a textile sleeve directly on said uncured elastomeric tube; (c)applying a rubber insulation layer over said textile sleeve; (d)applying a shape-restoring layer of a braided spiral sleeve around saidelastomeric tube, said braided spiral sleeve being composed of a firstbraid member of a relatively stiff, uncrimped monofilament selected fromthe group consisting of polyesters, copolyesters, aromatic polyamides,non-aromatic polyamides and fiberglass wound in a smooth helical pathabout said tube and a second braid member being braided with said firstbraid member wherein said second braide member deforms around said firstmember at each point of contact between said first and second braidmembers, said second braid member being composed of a plurality ofrelatively flexible, crimped textile filaments and wherein the tensionof the first and second braid members are substantially equal, saidfirst braid member being wound in a smooth helical path such that eachadjacent wrap of monofilament is widely spaced from the preceding wrapsuch that wide interstices are created between the first and secondbraid members thereby allowing for subsequent flow through saidinterstices; (e) extruding a cover of elastomer such that the elastomerextrudes through said interstices to intimately contact said rubberinsulation layer.